The problem of terminating roof systems at the periphery of a roof, especially a rigid roof, in an easy and waterproof manner is a problem that has long plagued builders. As a result of this problem, the National Roofing Contractors Association has developed a Roofing and Waterproofing Manual setting forth standards by which roofs should be terminated. For example, the third edition of that work (published 1989) suggests the use of multiple layers of materials to achieve a waterproofing effect.
It is known that a metallic termination or flashing strip can be attached by conventional fasteners, such as screws, nails or rivets to the roof deck. However, since such fasteners necessarily penetrate the roof structure, they provide a site for water leakage, requiring further coverage of the fastener site. Conventional roofing practice would be to overcoat the penetration sites with waterproof mastic or the like. For example, U.S. Pat. No. 4,619,100 to Emblin, indicates that to further ensure the watertight integrity of the system, a secondary sealant layer is applied over the mechanical fastening screws and the overlapping edges of the adjacent skin sections. Emblin suggests that an area extending several inches from either side of the overlapping area be first brushed with a coat of fibrous plastic sealant material such as the commercially available "Plasticoat Sealant" produced by Elixir Industries, after which a membrane is applied over the sealant layer and a second layer of "Plasticoat Sealant" is then applied over membrane as shown.
While such a technique is effective, it makes removal of the roofing system for replacement, which is an almost inevitable occurrence, a difficult and labor intensive task. Additionally, this redundant utilization of material occurs with, at best, uncertain result.